Perl is executed on a (UNC)host. And from this host, where
Perl is executed, it could not access to your host, namely
where the Tidy.pm is located. Therefore the question if you
perform Perl and then make something like Ping to your host
(or something equivalent) I highly guess, you cannot reach
your localPC. Only one-way direction.

I'm not THAT Perl-expert, so I don't know how to make
something like Ping on THAT UNC-host. That's your task -
sorry, but have no other options available.

Other additional question: Is Tidy.pm somewhere found that
UNC-Host?
LeO2Leo ;)

1) How is it possible that perl runs on your machine, when it is
installed on the UNC-path? Or does this mean you have also
local installation? But still, I do not get it, how this local Perl
could be excecuted, when you specify a remote one.

2) How do you come to the conclusion of your last paragraph?
i.e. from where could you detect Tidy.pm was running?

Perl is installed on some file server (unc path). But when you
execute it, it doesn't run on that file server, it runs on the
computer where you are running it from (aka, the perl.exe is
executing on my local machine).

By examining the @INC path, I looked for Tidy.pm and only
the one in the plug in is found.